---
title: IBM 5100
categories:
- Computers
types:
- Professional Computer
origins:
- U.S.A.
years:
- '1975'
cpus:
- IBM circuit module
params:
  name: '5100'
  image: /media/museum/photos/ibm_5100_system_1.jpg
  company: /companies/ibm
  company_name: IBM
  specs:
  - label: NAME
    value: '5100'
  - label: MANUFACTURER
    value: IBM
  - label: TYPE
    value: Professional Computer
  - label: ORIGIN
    value: U.S.A.
  - label: YEAR
    value: September 1975
  - label: END OF PRODUCTION
    value: '1978'
  - label: BUILT IN LANGUAGE
    value: BASIC or APL or both
  - label: KEYBOARD
    value: Full stroke 74 keys with numeric keypad and arrow keys
  - label: CPU
    value: IBM circuit module
  - label: SPEED
    value: 1.9 MHz.
  - label: RAM
    value: 16 KB to 64 KB by 16 KB steps
  - label: ROM
    value: 32 KB to 64 KB
  - label: TEXT MODES
    value: 64 chars. x 16 lines
  - label: GRAPHIC MODES
    value: None
  - label: COLORS
    value: Monochrome
  - label: SOUND
    value: No sound capabilities
  - label: SIZE / WEIGHT
    value: 24 Kg.
  - label: I/O PORTS
    value: 5103 printer and 5106 external tape drive unit
  - label: BUILT IN MEDIA
    value: Built-in 204 KB DC600 tape drive
  - label: OS
    value: APL or BASIC
  - label: POWER SUPPLY
    value: Built-in power supply unit
  - label: PRICE
    value: From $8975 (BASIC 16 KB) to $19,975 (BASIC+APL 64 KB)
  tabs:
  - photos
  - adverts
  - hardware
  - links
  forum_thread: 776
  photos:
  - title: FRONT VIEW
    subtitle: ''
    text: |-
      BASIC only model (no APL) with no tape drive.

      Thanks to redrum76 for this picture
    image: /media/museum/photos/ibm_5100_front_1.jpg
  - title: FRONT PANEL
    subtitle: ''
    text: |-
      A close-up of the controls.

      **(1)** Brightness adjustment\
      **(2)** Power switch\
      **(3)** Display left 32 cols, all 64 cols, or right 32 cols\
      **(4)** Process Check Led\
      **(5)** In Progress Led\
      **(6)** Display reverse switch\
      **(7)** Tape cartridge door\
      **(8)** Restart switch\
      **(9)** Display Registers switch
    image: /media/museum/photos/ibm_5100_frontpanel_1.jpg
  - title: MEMORY DUMP
    subtitle: ''
    text: Memory dump in hexadecimal form.
    image: /media/museum/photos/ibm_5100_hexadump_1.jpg
  - title: DISPLAY CLOSE-UP
    subtitle: ''
    text: Thanks to redrum76 for this picture
    image: /media/museum/photos/ibm_5100_display.jpg
  - title: DETAIL
    subtitle: ''
    text: Thanks to redrum76 for this picture
    image: /media/museum/photos/ibm_5100_detail_1.jpg
  adverts:
  - title: STRAPPING MAN!
    subtitle: ''
    text: |-
      Advert said:

      A compact problem-solving add for engineers, statisticians, scientists and financial and business analysts.
    image: /media/museum/pubs/ibm_5100_pub_1.jpg
  hardware:
  - title: 5103 PRINTER
    subtitle: ''
    text: 132-column bidirectional dot matrix printer with tractor feed. 80 characters per second.
    image: /media/museum/hardware/ibm_5120_printer5103_1.jpg
  - title: 'ESSENTIAL ACCESSORY #1'
    subtitle: ''
    text: ''
    image: /media/museum/hardware/ibm_5100_tshirt_1.jpg
  - title: 'ESSENTIAL ACCESSORY #2'
    subtitle: ''
    text: ''
    image: /media/museum/hardware/ibm_5100_cup_1.jpg
  links:
  - title: Eric's Eccentric Emporium of Egregiously Effervescent Effluvium, Etc - 5100 page
    url: http://www.brouhaha.com/~eric/retrocomputing/ibm/5100/
    text: Détailed page with interesting info
  - title: IBM 5110 page
    url: http://computermuseum.informatik.uni-stuttgart.de/dev/ibm_5110/technik/en/
    text: Very complete information here !
  - title: oldcomputers.net
    url: http://oldcomputers.net/ibm5100.html
    text: Nice article with good pictures
  - title: Wikipedia - IBM 5100 article
    url: http://en.wikipedia.org/wiki/IBM_5100
    text: Nice article
  related:
  - /museum/ibm-5120
  oc_id: 795
  source:
    url: https://web.archive.org/web/20230405101343/http://www.old-computers.com/museum/computer.asp?c=795
    date: '2023-04-05'
---

In September 1975, IBM announced its smallest and first portable computer (If you consider a 28 Kgs. computer portable, that is), the IBM 5100, no bigger than one of IBM's typewriters.

Developed in Rochester, it used the same operating system as IBM's /370 line of main frames. Thus it could accommodate the same APL interpreter, permitting the use of APL programs. A BASIC interpreter was also available, depending of the 5100 version chosen.

This was the first widely marketed and supported personal computer, and definitely the first useful all-in-one, portable computer system. However, it was a very primitive machine that was largely unsuccessful due to its high price tag (basic version costed $8,975) and limited expansion capabilities.

It had a built-in tape drive and a small 5" 64 character display. A special display mode allowed the user to select right or left bigger 32 chars. of each line.\
The tape drive used a 1/4 inch DC300 tape cartridge and stored 204 KB of data.\
The 5100 didn't feature a microprocessor chip, but a card called PALM (Put All Logic in Microcode) which acted as a 16-bit microprocessor.

Notice that the 5100 is the first serial number of IBM "Personal Computer" range that will later include the 5110, [5120](/museum/ibm-5120/), [5150](/museum/ibm-pc-model-5150/) (IBM-PC) and [5160](/museum/ibm-pc-xt-model-5160/) (PC-XT).